Integrated Cooling, Heating, and Power Systems

ABSTRACT

One exemplary embodiment of this invention provides a single-effect absorption chiller including an absorber operatively connected to a solution heat exchanger and a generator, and a condenser in fluid communication with the absorber, wherein the absorber is sized and configured to receive a feed of water from a source of water and to transfer heat to the feed of water and then to convey the feed of water to the condenser without further heat conditioning of the feed of water prior to its entry into the condenser, and wherein the condenser is sized and configured to receive the feed of water from the absorber and to transfer heat to the feed of water, thereby cooling the condenser without resorting to an external heat exchanger such as a conventional cooling tower.

TECHNICAL FIELD

This invention relates to the field of integrated cooling, heat, andpower systems.

BACKGROUND

Various efforts have been made to provide combined cooling, heat, andpower systems. However, the known systems all have their drawbacks. Forexample, in the range of distributed generation which is less than 200kW, which is known in the art as “micro” or “microgeneration,” theelectric power generation efficiency is relatively low. Therefore, it isvaluable to consider poly-generation, for example combined heating andpower (CHP), as a practice for small power or heat needs.

Almost all of the current combined cooling, heating, and power (CCHP)applications have been designed and installed using existing commercialproducts. Typically they consist of a power generator, a heat recoveryunit (HRU), a cooling system (an electrical compression system or anabsorption chilling system), and a cooling tower. For residential orsmall business applications, the current practice is too complicated,bulky, expensive, and intimidating. Furthermore, the overallthermal/electric efficiency of existing micro-CCHP systems are generallybelow 70% and hover at 65% due to the small sizes of each component andthe additional irreversibility generated between individual commercialunits.

Thus, a need continues to exist for an integrated CCHP system whichovercomes one or more of the aforementioned deficiencies of knownsystems.

SUMMARY OF THE INVENTION

This invention addresses this need by providing, amongst other things, amethod of integrating a gas turbine, an absorption chiller, and a gasturbine inlet chiller into a compact module. This invention furtherprovides a method for producing a large and constant electric power byusing a gas turbine inlet cooling technology. Also, this inventionprovides a method of integrating the heat recovery unit into a generatorof the absorption chiller system to eliminate the stand-alone heatrecovery system, as well as a method of removing the cooling tower byincorporating the condenser cooling system in the absorber of theabsorption chiller. This will significantly reduce the footprint andsize of the CCHP system, increase the system performance, and make iteasy to transport, install, and control.

In one embodiment of this invention there is provided a single-effectabsorption chiller, comprising an absorber operatively connected to asolution heat exchanger and a generator, and a condenser in fluidcommunication with the absorber, wherein the absorber is sized andconfigured to receive a feed of water from a source of water and totransfer heat to the feed of water and then to convey the feed of waterto the condenser without further heat conditioning of the feed of waterprior to its entry into the condenser, and wherein the condenser issized and configured to receive the feed of water from the absorber andto transfer heat to the feed of water, thereby cooling the condenserwithout resorting to an external heat exchanger such as a conventionalcooling tower.

Yet another embodiment of this invention provides is a single-effectabsorption chiller, comprising an absorber operatively connected to asolution heat exchanger and a generator, and a condenser operativelyconnected to a heat exchanger component of the generator, wherein thecondenser is sized and configured to receive a feed of water from asource of water and to transfer heat to the feed of water and then toconvey the feed of water to the heat exchanger component of thegenerator and to transfer heat to the feed of water from an externalheat source to provide hot water without resorting to an external heatrecovery unit.

Still another embodiment of this invention is a method comprisingproviding a refrigerant vapor to an absorber of a single-effectabsorption chiller in which at least the refrigerant vapor contacts anincoming condensed absorbent stream from a solution heat exchanger, therefrigerant vapor is absorbed by the condensed absorbent stream to forma liquid diluted solution mixture, and a water stream from a source ofwater is provided to cool the absorber to make a high affinity betweenthe refrigerant vapor and the condensed absorbent stream during theabsorption process and to transfer heat to the feed of water; providingthe water stream from the absorber to a condenser so that the waterstream absorbs at least a portion of released latent heat from thecondenser, thereby forming a condenser-heated water stream and coolingthe condenser without resorting to an external heat exchanger such as aconventional cooling tower; further heating the condenser-heated waterstream by feeding it into a generator through a heat exchanger componentwherein the condenser-heated water stream absorbs additional heat fromenergy from an external heat source to provide hot water withoutresorting to an external heat recovery unit; providing a second waterstream into an evaporator in which a low-temperature, low-pressurerefrigerant flashes into a vapor and absorbs heat from the second waterstream, thereby lowering the temperature of the second water stream andforming a chilled water stream; transferring at least a portion of thechilled water stream to an engine inlet chiller operatively connected toa combustion engine; and circulating exterior air through the engineinlet chiller.

In another embodiment of this invention, a multiple-effect absorptionchiller system is provided. The system comprises an absorber operativelyconnected to a solution heat exchanger and a generator, and an initialcondenser in fluid communication with the absorber, wherein the absorberis sized and configured to receive a feed of water from a source ofwater and to transfer heat to the feed of water and then to convey thefeed of water to the initial condenser without further heat conditioningof the feed of water prior to its entry into the initial condenser, andwherein the initial condenser is sized and configured to receive thefeed of water from the absorber and to transfer heat to the feed ofwater, thereby cooling the initial condenser without resorting to anexternal heat exchanger such as a conventional cooling tower.

Still another embodiment of this invention is a multiple-effectabsorption chiller system, comprising an absorber operatively connectedto a solution heat exchanger and a generator, and

a condenser operatively connected to a heat exchanger component of aterminal generator, wherein the condenser is sized and configured toreceive a feed of water from a source of water that has not beenintentionally heat conditioned and to transfer heat to the feed of waterand then to convey the feed of water to the heat exchanger component ofthe generator, the heat exchanger component of the generator being sizedand configured to receive the feed of water and to transfer heat to thefeed of water from an external heat source without resorting to anexternal heat recovery unit.

In yet another embodiment of the invention, a method is provided whichcomprises providing a refrigerant vapor to an absorber in amultiple-effect absorption chiller in which at least the refrigerantvapor contacts an incoming condensed absorbent stream from a solutionheat exchanger, the refrigerant vapor is absorbed by the condensedabsorbent stream to form a liquid diluted solution mixture, and a waterstream from a source of water is provided to cool the absorber to make ahigh affinity between the refrigerant vapor and the condensed absorbentstream during the absorption process and to transfer heat to the feed ofwater; providing the water stream from the absorber to an initialcondenser so that the water stream absorbs at least a portion ofreleased latent heat from the initial condenser, thereby forming aninitial-condenser-heated water stream and cooling the initial condenserwithout resorting to an external heat exchanger such as a conventionalcooling tower; further heating the initial-condenser-heated water streamby feeding it into a terminal generator through a heat exchangercomponent wherein the initial-condenser-heated water stream absorbsadditional heat from energy from an external heat source to provide hotwater without resorting to an external heat recovery unit; providing asecond water stream into an evaporator in which a low-temperature,low-pressure refrigerant flashes into vapor and absorbs heat from thesecond water stream, thereby lowering the temperature of the secondwater stream and forming a chilled water stream; transferring at least aportion of the chilled water stream to an engine inlet chilleroperatively connected to a combustion engine; and circulating exteriorair through the engine inlet chiller.

A system provided in yet another embodiment of this invention comprisesa combustion engine, a single-effect absorption chiller in accordancewith the teachings herein, an engine inlet chiller operatively connectedto at least the combustion engine, and a conduit for conveying chilledwater from the absorption chiller to the engine inlet chiller, theforegoing being sized and configured so that, during use, waste heatreleased from the combustion engine powers the generator of thesingle-effect absorption chiller. The single-effect absorption chillerprovides space cooling as well as produces chilled water, and the systemis sized and configured to circulate at least a portion of the chilledwater through the conduit back to the engine inlet chiller to cool airentering the combustion engine.

Another embodiment of this invention is a system comprising: acombustion engine, a multiple-effect absorption chiller in accordancewith the teachings herein, an engine inlet chiller operatively connectedto at least the combustion engine, and a conduit for conveying chilledwater from the absorption chiller to the engine inlet chiller, theforegoing being sized and configured so that, during use, waste heatreleased from the combustion engine powers at least one internalgenerator of the multiple-effect absorption chiller. The multiple-effectabsorption chiller provides space cooling as well as produces chilledwater, and the system being sized and configured to circulate at least aportion of the chilled water through the conduit to the engine inletchiller to cool air entering the combustion engine.

These and other embodiments, features and benefits of this inventionwill be still further apparent from the ensuing description,accompanying figures and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a combined cooling, heat and power system withinlet cooling and an integrated heat recovery unit inside thesingle-effect absorption chiller system. In this embodiment of theinvention, the cooling tower and the stand-alone HRU are removed.

FIG. 2 is a diagram of a single-effect absorption chiller. In thisembodiment, the heat recovery unit and the equivalent effect of coolingtower are embedded in the single-effect absorption chiller.

FIG. 3 is a diagram of a double-effect absorption chiller. In thisembodiment, the heat recovery unit and the equivalent effect of coolingtower are embedded in the double-effect absorption chiller.

Like reference numbers or letters employed within the various figuresrefer to like parts or components.

FURTHER DETAILED DESCRIPTION OF THE INVENTION

Gas turbine inlet cooling is extremely effective in counteracting thedecreasing micro-gas turbine performance during the hot and humid summerwhen the power demand reaches maximum levels. Employing gas turbineinlet cooling minimizes the effect of ambient temperature and moistureon the electricity output of the gas turbine because gas turbine outputis a strong function of ambient temperature and typically loses between0.3% and 0.5% of their ISO rated power for every 1° F. rise in inlettemperature. In the engine size considered (nominal 28 kW), a typicalmicro-gas turbine engine, without using a recuperator (such as theCapstone model 330), is evaluated with a conversion efficiency rated atapproximately 23% (HHV) of fuel input (full load ratings with no systemloads or duration applied). Unfortunately, similar to the engine poweroutput, its efficiency is also affected by ambient conditions, andefficiency drops to about 19% (HHV) at 86° F. This roughly equates to aneffective heat rate of about 17,963 Btu/kWh.

To compensate for the degradation of efficiency and power output, anumber of Turbine Inlet Cooling (TIC) technologies can be employed toincrease the mass-flow through the combustion turbine by cooling theinlet air. Cooler air is denser, and since combustion turbines areconstant volume flow machines, denser air equates to greater mass flow.Options to improve micro-gas turbine performance through inlet coolingare numerous, including both indirect evaporative “pre-cooling” systems,active “chiller” refrigeration based systems (both electrically drivenand thermally driven), desiccant cooling systems, and a number of waterspray/fogging options. However, these methods known in the art haveknown drawbacks. Particularly, in regions where summers are hot andhumid, evaporative cooling and fogging method are not effective to bringdown the temperature. In order to combat such problems, the firstembodiment of the present invention, depicted in FIG. 1, employs atleast a portion of the chilled water from either a single-effect ormultiple-effect absorption chiller to cool the inlet air of the gasturbine. Also, in this first embodiment of the present invention, thesingle-effect or multiple-effect absorption chiller may employ anycombination of refrigerant/absorbent solutions. Preferredrefrigerant/absorbent solutions are water/lithium bromide andammonia/water, with water/lithium bromide solution being most preferred.Particularly, lithium bromide is most desirable for cooling above thefreezing point.

As demonstrated in certain embodiments of the present invention, asingle-effect or multiple-effect absorption chiller is a bettercandidate to provide inlet air cooling than existing technologies,especially when the requirement for hot water diminishes in summermonths. Also, during the summer, excess heat can be effectively utilizedas an energy source for the single-effect or multiple-effect absorptionchiller. Therefore, as shown in FIG. 1, a first embodiment of thisinvention integrates an absorption chiller system with the micro-gasturbine to provide turbine inlet air-cooling, boost fuel-electricityefficiency, and power output in summer.

A single-effect or multiple-effect absorption chiller employed as partof the system of the first embodiment of this invention provides spacecooling as well as cooling for the turbine inlet air. Cooling of theturbine inlet air in this manner allows the air to be cooled down to atleast the ISO condition (59° F. and 60% relative humidity) during thehot days. By employing the first embodiment of the present invention byusing turbine inlet air cooling with a micro-gas turbine engine to coolthe inlet air to at least the ISO condition, the electric power outputcan be enhanced by up to approximately 17%, and possibly more in certaincases, on 85° F. days. By providing at least a portion of the chilledwater from the outlet of the absorption chiller to further cool theinlet air of the micro-gas turbine to 42° F., the electric power outputcan be enhanced by up to approximately 27%, and possibly more in certaincases, on 85° F. days also by employing the first embodiment of thepresent invention. Thus, in some embodiments, by providing at least aportion of the chilled water from the outlet of the absorption chillerto cool the inlet air of the micro-gas turbine, the electric poweroutput enhancement is in the range of about 5% to about 27%, while inother embodiments the enhancement may be in the range of about 10% toabout 27%, by employing the first embodiment of the present invention on85° F. days. By providing at least a portion of the chilled water fromthe outlet of the absorption chiller to cool the inlet air of themicro-gas turbine from 95° F. to at least the ISO condition (59° F.),the electric power output can be enhanced by up to approximately 20%,and possibly more in certain cases, on 95° F. days also by employing thefirst embodiment of the present invention. By providing at least aportion of the chilled water from the outlet of the absorption chillerto further cool the inlet air of the micro-gas turbine to 42° F., theelectric power output can be enhanced by up to approximately 30%, andpossibly more in certain cases, on 95° F. days also by employing thefirst embodiment of the present invention. Thus, in some embodiments,the electric power output enhancement is in the range of about 5% toabout 30%, while in other embodiments the enhancement may be in therange of about 10% to about 30% on 95° F. days. The range of electricpower output enhancement by utilization of any embodiment of the presentinvention is susceptible to considerable variation within the spirit andscope of the appended claims. Also, in addition to providing electricpower output enhancement, by employing this turbine inlet air coolingtechnology, a gas turbine is able to produce output power at a constantrate, as typical output power rates are dependent on the ambienttemperature surrounding the gas turbine. Employing the turbine inlet aircooling technology of this invention moderates the changes intemperature of the inlet air and thus provides a more constant outputpower rate.

Also, if more electricity power is needed, the micro-gas turbine inlettemperature can further cool down to 42° F. and increase electric poweroutput by approximately 10%. However, for micro-gas turbineapplications, the inlet air should not be cooled below about 40° F. toavoid frosting that may result from the loss of static temperature whenthe air is accelerated into the compressor.

The operating performance of a micro-CCHP system involves complexinteractions and tradeoffs between three systems: the recuperatedBrayton cycle system, the absorption refrigeration system, and the heatrecovery system. Also, the First and Second Laws of Thermodynamics,regarding energy analysis and entropy production, respectively, areapplied in optimizing the efficiency of this combined system.

A second embodiment of this invention depicted in FIG. 2 eliminates theneed for a stand-alone HRU and a cooling tower, which are necessary inknown systems, by adding a heat exchanger to the generator of thesingle-effect absorption chiller and by utilizing a feed of water from asource as a cooling system in the absorber and in the condenser of theabsorption chiller.

In known single-effect absorption chillers, the generator serves as aliquid-vapor separator and usually occupies a relatively large volume.However, in the second embodiment of the present invention, a heatexchanger component of the generator allows water to pass through thegenerator in a separate path and be heated by turbine exhaust gas, asshown in FIG. 2. This design can remove the current HRU used in knownsystems and take advantage of the generator's volume for heating water.This integration will significantly reduce the space, cost, and systemirreversibility.

Also, by using the second embodiment of the present invention, asdemonstrated in FIG. 2, the cooling tower employed with mostsingle-effect absorption chillers in known systems can be removed byusing a feed of water from a source through the absorber and then byredirecting the feed of water from the absorber to the condenser, soenergy released from the condenser can be effectively utilized. In knowncommercial absorption chiller systems, cooling of the condenser isprovided by water operated in a closed loop outside the absorptionchiller system. In the new design, water from a source (such as tap,city, or well water) will be fed as the cooling water where it will (a)enter the absorber and absorb the heat released, (b) continue to enterthe condenser and absorb the latent heat released by the condensingrefrigerant, and (c) the feed of water (which has become warm at thisstage) is routed through the heat exchanger component of the generatorto be heated by hot exhaust gas. In this manner, the stand-alone coolingtower of the conventional absorption chiller can be removed. A thirdembodiment of this invention depicted in FIG. 3 eliminates the need fora stand-alone HRU and cooling tower, as are necessary in known systems,by adding a heat exchanger to the terminal generator of themultiple-effect absorption chiller and by utilizing a feed of water froma source as a cooling system in the absorber of the multiple-effectabsorption chiller.

In known multiple-effect absorption chillers, the terminal generatorserves as a liquid-vapor separator and usually occupies a relativelylarge volume. However, in the third embodiment of the present invention,a heat exchanger component of the terminal generator allows water topass through the terminal generator in a separate path and be heated byturbine exhaust gas, as shown in FIG. 3. This design can remove thecurrent HRU used in known systems and take advantage of the terminalgenerator's volume for heating water. This integration willsignificantly reduce the space, cost, and system irreversibility.

Also, by using the third embodiment of the present invention, asdemonstrated in FIG. 3, the cooling tower employed with mostmultiple-effect absorption chillers in known systems can be removed byusing a feed of water from a source through the absorber and then byredirecting the feed of water from the absorber to the initialcondenser, so energy released from the initial condenser can beeffectively utilized. In known commercial multiple-effect absorptionchiller systems, cooling of the initial condenser is provided by wateroperated in a closed loop outside the absorption chiller system. In thenew design, water from a source (such as tap, city, or well water) willbe fed as the cooling water where it will (a) enter the absorber andabsorb the heat released, (b) continue to enter the initial condenserand absorb the latent heat released by the condensing refrigerant, and(c) the feed of water (which has become warm at this stage) is routedthrough the heat exchanger component of the terminal generator to beheated by hot exhaust gas. In this manner, the stand-alone cooling towerof the conventional multiple-effect absorption chiller can be removed.

Turning now to the particulars of the figures, as noted above, FIG. 1depicts one particular embodiment of the present invention. There itwill be seen that the depicted combined cooling, heat, and power systemcomprises a combustion engine 10, an absorption chiller 12A, an engineinlet chiller 14, and a conduit for conveying chilled water 16 from theabsorption chiller 12A to the engine inlet chiller 14, the foregoingbeing sized and configured so that, during use, waste heat released 24from the combustion engine 10 powers a generator 26 of the absorptionchiller 12A. The absorption chiller 12A produces chilled water 20 whichprovides, at least in part, space cooling 18, and the system isconfigured to circulate at least a portion of the chilled water 20through the conduit 16 to the engine inlet chiller 14 to cool air 22entering the combustion engine 10 and then to circulate at least of aportion of the water 28 from the engine inlet chiller 14 back to theabsorption chiller 12A to repeat the cycle.

FIG. 2 depicts another particular embodiment of the present invention.There it will be seen that the depicted single-effect absorption chiller12 comprises an absorber 30, a solution heat exchanger 32, a generator26, a heat exchanger component 34 of the generator 26, condenser 36, apump 46, an evaporator 48, and a throttling valve 58. The foregoingcomponents are sized and configured so that, during use, a water stream28 is provided to the evaporator 48 wherein a low-temperature,low-pressure refrigerant in the evaporator 48 flashes into vapor andabsorbs heat from the water stream 28 thereby lowering the temperatureof the water stream 28 and producing chilled water 20. The refrigerantvapor 40 is provided to an absorber 30 in which at least the refrigerantvapor 40 contacts an incoming condensed absorbent stream 42 from asolution heat exchanger 32, the refrigerant vapor 40 is absorbed by thecondensed absorbent stream 42 to form a liquid diluted solution mixture44, and feed of water from a water source 38 is provided to cool theabsorber 30 to make a high affinity between the refrigerant vapor 40 andthe condensed absorbent stream 42 during the absorption process. Using apump 46, the liquid diluted solution mixture 44 is pumped to asufficient pressure and to the solution heat exchanger 32 in which heatis transferred from the condensed absorbent stream 42 to the liquiddiluted solution mixture 44 creating a preheated liquid diluted solutionmixture 50. The preheated liquid diluted solution mixture 50 is providedto the generator 26. The preheated liquid diluted solution mixture 50 isheated in the generator 26 to a sufficient temperature using heat froman external heat source 62 so as to re-vaporize at least a portion ofthe refrigerant in the preheated liquid diluted solution mixture 50,thereby separating the preheated liquid diluted solution mixture into asuperheated refrigerant vapor 52 and a condensed absorbent stream 42.The superheated refrigerant vapor 52 is provided to a condenser 36 inwhich it is maintained at substantially the same pressure as in thegenerator 26, and the superheated refrigerant vapor 52 is converted backto a saturated liquid phase in the condenser 36 so as to form condensedrefrigerant 56 and release latent heat. The feed of water 38 is providedfrom the absorber 30 to the condenser 36 so that the feed of water 38absorbs at least a portion of the released latent heat from thecondensed refrigerant, thereby forming a condenser-heated water stream54 and cooling the condenser 36 and further heating the condenser-heatedwater stream 54 by feeding it into the generator 26 through a heatexchanger component 34 of the generator 26, wherein the condenser-heatedwater stream 54 absorbs additional heat from energy remaining from theexternal heat source 62. The condensed refrigerant 56 is fed through athrottling valve 58, wherein the pressure of the condensed refrigerant56 is reduced so as to flash the condensed refrigerant 56 therebyforming a flashed refrigerant vapor 60. At least a portion of theflashed refrigerant vapor 60 is then recycled back to the evaporator,and at least a portion of the condensed absorbent stream 42 is recycledback to the solution heat exchanger 32.

FIG. 3 is a diagram of another particular embodiment of the presentinvention. There it will be seen that the depicted double-effectabsorption chiller 70 comprises evaporator 74, an absorber 78, aninitial solution heat exchanger 82, an initial pump 88, an initialgenerator 92, an initial condenser 110, an initial throttling valve 104,a terminal pump 108, a terminal solution heat exchanger 112, a terminalgenerator 118, a heat exchanger component 132 of the terminal generator118, a terminal condenser 94, and a terminal throttling valve 126. Theforegoing components are sized and configured so that, during use, afirst water stream 72 is provided to an evaporator 74 containing arefrigerant which absorbs heat from the first water stream 72 therebyforming a heated refrigerant 72 and lowering the temperature of thefirst water stream 72. The heated refrigerant 72 is provided to anabsorber 78 in which the heated refrigerant 76 directly contacts anincoming condensed absorbent stream 80 from an initial solution heatexchanger 82, the heated refrigerant 76 is absorbed by the condensedabsorbent stream 80 to form an liquid diluted solution mixture 84, and asecond water stream 86 is provided to cool the absorber 78 to make ahigh affinity between the refrigerant vapor 76 and the condensedabsorbent stream 80 during the absorption process. The liquid dilutedsolution mixture 84 is pumped using an initial pump 88 to a sufficientpressure and to an initial solution heat exchanger 82 in which heat istransferred from the condensed absorbent stream 80 to the liquid dilutedsolution mixture 84 creating a preheated liquid diluted solution mixture90. The preheated liquid diluted solution mixture 90 is fed to aninitial generator 92, and the preheated liquid diluted solution mixture90 is heated in the initial generator 92 to a sufficient temperatureusing heat from latent heat released from a terminal condenser 94 so asto re-vaporize at least a portion of the refrigerant in the preheatedliquid diluted solution mixture 90 thereby at least partially separatingthe preheated liquid diluted solution mixture into a superheatedrefrigerant vapor 96, a condensed absorbent stream 80, and a residualpreheated liquid diluted solution mixture 100. The superheatedrefrigerant vapor 96 is provided to an initial condenser 110 which ismaintained at substantially the same pressure as in the initialgenerator 92, and the superheated refrigerant vapor 96 is converted backto a saturated liquid phase in the initial condenser 110 so as to formcondensed refrigerant 102 and release latent heat. The pressure of thecondensed refrigerant 102 is reduced by using the initial throttlingvalve 104, so as to flash the condensed refrigerant 102 by reducing itspressure and temperature, thereby forming a flashed refrigerant vapor106. The flashed refrigerant vapor 106 is provided to the evaporator 74.The residual preheated liquid diluted solution mixture 100 is pumped toa sufficient pressure using a terminal pump 108 and to a terminalsolution heat exchanger 112, so that heat is transferred from thecondensed absorbent stream 114 to the residual preheated liquid dilutedsolution mixture 100 creating a preheated liquid diluted solutionmixture 116, and the preheated liquid diluted solution mixture 116 isfed to a terminal generator 118. The second water stream 86 is providedfrom the absorber 78 to the initial condenser 110 so that the secondwater stream 86 absorbs at least a portion of the released latent heatfrom the condensed refrigerant 102. The residual preheated liquiddiluted solution mixture 116 is heated in a terminal generator 118 to asufficient temperature using the heat from an external heat source 120,so as to re-vaporize at least a portion of the refrigerant in thepreheated liquid diluted solution mixture 116, thereby separating thepreheated liquid diluted solution mixture 116 into a superheatedrefrigerant vapor 122 and a condensed absorbent stream 114. Thesuperheated refrigerant vapor 122 is provided to the terminal condenser94 in which it is maintained at substantially the same pressure as inthe terminal generator 118. The superheated refrigerant vapor 122 isconverted back to a liquid phase in the terminal condenser 94, so as toform a condensed refrigerant 124 and release latent heat. Using aterminal throttling valve 126, the condensed refrigerant 124 is flashedby reducing its pressure and temperature, thereby forming a flashedrefrigerant vapor 128. The flashed refrigerant vapor 128 is provided tothe initial condenser 110, and the flashed refrigerant vapor 128 isconverted back to a saturated liquid phase in the initial condenser 110,thereby forming condensed refrigerant 102 and releasing latent heat.Using an initial throttling valve, the condensed refrigerant 102 isflashed by reducing its pressure and temperature, thereby forming aflashed refrigerant vapor 106. At least a portion of the flashedrefrigerant vapor 106 is recycled back to the evaporator 74, and atleast a portion of the condensed absorbent stream 80 is recycled back tothe evaporator 78. Finally, the second water stream 86 is further heatedby feeding it into the terminal generator 118 through a compact heatexchanger component 132 of the terminal generator 118 and heating thesecond water stream 86 using energy remaining from the external heatsource 120.

The core of a CCHP system comprises any power-generating deviceincluding gas turbines, reciprocating engines (spark ignition, diesel,and sterling engines), wind turbines, fuel cells, solar panels, andmini-hydro. Currently, reciprocating engines, particularly gas anddiesel, dominate the residential and small business markets. In thepresent invention, the use of combustion engines, such as reciprocatingengines and gas turbines, is most preferred.

For micro-CCHP, a system employing a micro-gas turbine with adouble-effect absorption chiller is most preferred. Since the exhaustgas from a micro-gas turbine is around 275° C., higher than those ofreciprocating engines, the embodiment employing a double-effectabsorption chiller takes advantage of a micro-gas turbine's higherexhaust gas temperature. Both the chilled water and hot water willincrease when a double-effect absorption chiller is employed. Thetradeoff to use a double-effect chiller is its bigger size andcomplexity.

As noted supra, the overall thermal/electric efficiency of existingmicro-CCHP systems are generally below 70% and hover at 65% due to thesmall sizes of each component and the additional irreversibilitygenerated between individual commercial units. In one embodiment of thisinvention, as depicted in FIG. 1, a combined cooling, heat, and powersystem comprises a combustion engine 10, an absorption chiller 12A, anengine inlet chiller 14, and a conduit for conveying chilled water 16from the absorption chiller 12A to the engine inlet chiller 14. Atypical heat recovery unit of a micro-CCHP system is integrated into agenerator of the absorption chiller (single-effect absorption chiller 12in FIG. 2; double-effect absorption chiller 70 in FIG. 3) of the presentinvention to eliminate the stand-alone heat recovery system, as well aseliminate the need for a cooling tower (or an equivalent cooling heatexchanger) by incorporating a condenser cooling system with the coolingwater coming from an outside source (38 in FIG. 2; 86 in FIG. 3) to theabsorber (30 in FIG. 2; 78 in FIG. 3) of the absorption chiller (12 inFIG. 2; 70 in FIG. 3). By integrating these components into a compactmodule and eliminating the stand-alone heat recovery system and coolingtower, this invention provides an integrated micro-CCHP utilizing amicro-gas turbine that is a high-efficiency system with excellentperformance. By using this embodiment of the present invention (12A inFIG. 1) in the realm of micro-CCHP technology, i.e., less than 200 kW,the micro-CCHP performance can be up to approximately 142.5%, andpossibly more in certain cases, when a single-effect absorption chiller(12 in FIG. 2) is used as the absorption chiller 12A in the embodimentdepicted in FIG. 1, and up to approximately 164.8%, and possibly more incertain cases, when a double-effect absorption chiller (70 in FIG. 3) isused as the absorption chiller 12A in the embodiment depicted in FIG. 1.It is noted that the overall performance of higher than 100% does notviolate the Second Law of Thermodynamics. The part of energy beyond 100%does not come from the fuel, but it is harvested from the environmentvia the absorption chiller 12A.

When the single-effect absorption chiller (12 in FIG. 2) is employed asthe absorption chiller 12A in FIG. 1, the micro-CCHP performance can beup to approximately 142.5%, and possibly more in certain cases, whichincludes 30% for electricity, 31.5% for chilled water, and 81% for hotwater. Specifically, for this embodiment of the present invention inFIG. 1, if 360,000 kJ/h of fuel is used in a micro-gas turbine 10, therewould result 29.6 kW of power produced (a performance of approximately30% for electricity produced) with a radiation loss of approximately6,000 kJ/h and approximately 242,000 kJ/h of waste heat released 24 fromthe combustion engine 10 to the absorption chiller 12A. Then, thesingle-effect absorption chiller 12 with embedded heat recovery unitreceives 242,000 kJ/h from the micro-gas turbine 10 and 117,000 kJ/hfrom the return water stream 28, and assuming a typical thermalcoefficient of performance of 0.68 for the single effect absorptionchiller, outputs 289,000 kJ/h in hot water at 68 degrees C., 22,000 kJ/hto loss, and 48,000 kJ/h to exhaust. Therefore, the resultingperformance of the single-effect absorption chiller 12 with embeddedheat recovery unit is approximately 81% for hot water produced. Also,there is 117,000 kJ/h, or 31.5% performance, for chilled water 20produced by the single-effect absorption chiller 12. Therefore, as canbe seen from the above figures, for every 100 kW of fuel input into themicro-gas turbine, up to approximately 142.5 kW performance is achieved.Again, it is noted that the overall performance of higher than 100% doesnot violate the Second Law of Thermodynamics. The part of energy beyond100% does not come from the fuel, but it is harvested from theenvironment via the absorption chiller 12A. The cooling capacity, 31.5kW from the chilled water, is counted twice—first as the coolingperformance and later recovered by the hot water.

When the double-effect absorption chiller (70 in FIG. 4) is employed asthe absorption chiller 12A in FIG. 1, the micro-CCHP performance can beup to approximately 164.8%, and possibly more in certain cases, whichincludes 30% for electricity, 43.3% for chilled water, and 91.4% for hotwater. Specifically, for this embodiment of the present invention inFIG. 1, if 360,000 kJ/h of fuel is used in a micro-gas turbine 10, therewould result 29.6 kW of power produced (a performance of approximately30% for electricity produced) with a radiation loss of approximately6,000 kJ/h and approximately 242,000 kJ/h of waste heat released 24 fromthe combustion engine 10 to the absorption chiller 12A. Then, thedouble-effect absorption chiller 70 with embedded heat recovery unitreceives 242,000 kJ/h from the micro-gas turbine 10 and 156,000 kJ/hfrom the return water stream 72, and assuming a typical thermalcoefficient of performance of 1.3 for the double-effect absorptionchiller 70, outputs 328,000 kJ/h in hot water at 68 degrees C., 22,000kJ/h to loss, and 48,000 kJ/h to exhaust. Therefore, the resultingperformance of the double-effect absorption chiller 70 with embeddedheat recovery unit is approximately 91.4% for hot water produced. Also,there is 156,000 kJ/h, or 43.3% performance, for chilled water producedby the double-effect absorption chiller 70. Therefore, as can be seenfrom the above figures, for every 100 kW of fuel input into themicro-gas turbine, up to approximately 164.8% performance is achieved.Again, it is noted that the overall performance of higher than 100% doesnot violate the Second Law of Thermodynamics. The part of energy beyond100% does not come from the fuel, but it is harvested from theenvironment via the absorption chiller 70.

Known micro-CHP systems only convert waste heat to hot water, andconsequently, only the fuel cost of the hot water is saved. Conversely,using the above embodiments of the present invention, a resultingmicro-CCHP system can provide an overall performance of up toapproximately 142.5%, and possibly more in certain cases, when asingle-effect absorption chiller (12 in FIG. 2) is used as theabsorption chiller 12A in the embodiment depicted in FIG. 1, and up toapproximately 164.8%, and possibly more in certain cases, when adouble-effect absorption chiller (70 in FIG. 3) is used as theabsorption chiller 12A in the embodiment depicted in FIG. 1. Thecapability to produce more electricity and chilled water is moreimportant than producing hot water, especially in rural areas inunderdeveloped countries because villagers can generate hot water usingtraditional biomass such as wood and agriculture residue. Also, it isnoted that even though the foregoing discussion was limited to the realmof micro-CCHP systems, there is a similar enhancement in larger systemsemploying embodiments of this invention as well, such as 1 MW, 50 MW,250 MW, etc.

In all of the embodiments of the present invention, the single-effect ormultiple-effect absorption chiller employed may use any combination ofrefrigerant/absorbent solutions. Preferred refrigerant/absorbentsolutions are water/lithium bromide and ammonia/water, withwater/lithium bromide solution being most preferred.

It should be appreciated that, while specific embodiments are describedabove, several other variants of those embodiments may be contemplatedby those of ordinary skill in the art in view of this disclosure, thosevariants nevertheless falling within the spirit and scope of the presentinvention. Accordingly, the scope of this invention is not limited tothe specific embodiments described in detail above.

1. A single-effect absorption chiller, comprising: an absorberoperatively connected to a solution heat exchanger and a generator, anda condenser in fluid communication with the absorber, wherein theabsorber is sized and configured to receive a feed of water from asource of water, and to transfer heat to the feed of water and then toconvey the feed of water to the condenser without further heatconditioning of the feed of water prior to its entry into the condenser,and wherein the condenser is sized and configured to receive the feed ofwater from the absorber and to transfer heat to the feed of water,thereby cooling the condenser.
 2. The single-effect absorption chillerof claim 1, further comprising a heat exchanger component of thegenerator, wherein the heat exchanger component of the generator issized and configured to receive the feed of water from the condenser andto transfer heat to the feed of water from an external heat source.
 3. Asingle-effect absorption chiller, comprising: an absorber operativelyconnected to a solution heat exchanger and a generator, and a condenseroperatively connected to a heat exchanger component of the generator,wherein the condenser is sized and configured to receive a feed of waterfrom a source of water and to transfer heat to the feed of water andthen to convey the feed of water to the heat exchanger component of thegenerator and to transfer heat to the feed of water from an externalheat source.
 4. A method comprising: a. providing a refrigerant vapor toan absorber of a single-effect absorption chiller in which at least i.the refrigerant vapor contacts an incoming condensed absorbent streamfrom a solution heat exchanger, ii. the refrigerant vapor is absorbed bythe condensed absorbent stream to form a liquid diluted solutionmixture, and iii. a water stream from a source of water is provided tocool the absorber to make a high affinity between the refrigerant vaporand the condensed absorbent stream during the absorption process in(a)(ii) and to transfer heat to the feed of water; b. providing thewater stream from the absorber to a condenser so that the water streamabsorbs at least a portion of released latent heat from the condenser,thereby forming a condenser-heated water stream and cooling thecondenser; and c. further heating the condenser-heated water stream byfeeding it into a generator through a heat exchanger component whereinthe condenser-heated water stream absorbs additional heat from energyfrom an external heat source.
 5. The method of claim 4 furthercomprising: d. providing a second water stream into an evaporator inwhich a low-temperature, low-pressure refrigerant flashes into vapor andabsorbs heat from the second water stream, thereby lowering thetemperature of the second water stream and forming a chilled waterstream.
 6. The method of claim 5 further comprising: e. transferring atleast a portion of the chilled water stream to an engine inlet chilleroperatively connected to a combustion engine, and f. circulatingexterior air through the engine inlet chiller.
 7. A multiple-effectabsorption chiller system, comprising: an absorber operatively connectedto a solution heat exchanger and a generator, and an initial condenserin fluid communication with the absorber, wherein the absorber is sizedand configured to receive a feed of water from a source of water and totransfer heat to the feed of water and then to convey the feed of waterto the initial condenser without further heat conditioning of the feedof water prior to its entry into the initial condenser, and wherein theinitial condenser is sized and configured to receive the feed of waterfrom the absorber and to transfer heat to the feed of water, therebycooling the initial condenser.
 8. The multiple-effect absorption chillersystem of claim 5, further comprising a heat exchanger component of aterminal generator wherein the heat exchanger component of the terminalgenerator is sized and configured to receive the feed of water from theinitial condenser and to transfer heat to the feed of water from anexternal heat source.
 9. A multiple-effect absorption chiller system,comprising: an absorber operatively connected to a solution heatexchanger and a generator, and a condenser operatively connected to aheat exchanger component of a terminal generator, wherein the condenseris sized and configured to receive a feed of water from a source ofwater that has not been intentionally heat conditioned and to transferheat to the feed of water and then to convey the feed of water to theheat exchanger component of the generator, the heat exchanger componentof the generator being sized and configured to receive the feed of waterand to transfer heat to the feed of water from an external heat source.10. A method comprising: a. providing a refrigerant vapor to an absorberin a multiple-effect absorption chiller in which at least i. therefrigerant vapor contacts an incoming condensed absorbent stream from asolution heat exchanger, ii. the refrigerant vapor is absorbed by thecondensed absorbent stream to form a liquid diluted solution mixture,and iii. a water stream from a source of water is provided to cool theabsorber to make a high affinity between the refrigerant vapor and thecondensed absorbent stream during the absorption process in (a)(ii) andto transfer heat to the feed of water; b. providing the water streamfrom the absorber to an initial condenser so that the water streamabsorbs at least a portion of released latent heat from the initialcondenser, thereby forming an initial-condenser-heated water stream andcooling the initial condenser; and c. further heating theinitial-condenser-heated water stream by feeding it into a terminalgenerator through a heat exchanger component wherein theinitial-condenser-heated water stream absorbs additional heat fromenergy from an external heat source.
 11. The method of claim 10 furthercomprising: d. providing a second water stream into an evaporator inwhich a low-temperature, low-pressure refrigerant flashes into vapor andabsorbs heat from the second water stream, thereby lowering thetemperature of the second water stream and forming a chilled waterstream.
 12. The method of claim 11 further comprising: e. transferringat least a portion of the chilled water stream to an engine inletchiller operatively connected to a combustion engine, and f. circulatingexterior air through the engine inlet chiller.
 13. A system comprising:a combustion engine, a single-effect absorption chiller according toclaim 3, an engine inlet chiller operatively connected to at least thecombustion engine, and a conduit for conveying chilled water from theabsorption chiller to the engine inlet chiller, the foregoing beingsized and configured so that, during use, waste heat released from thecombustion engine powers the generator of the single-effect absorptionchiller, which single-effect absorption chiller produces chilled water,and the system being sized and configured to circulate at least aportion of the chilled water through the conduit to the engine inletchiller to cool air entering the combustion engine.
 14. A systemcomprising: a combustion engine, a multiple-effect absorption chilleraccording to claim 9, an engine inlet chiller operatively connected toat least the combustion engine, and a conduit for conveying chilledwater from the absorption chiller to the engine inlet chiller, theforegoing being sized and configured so that, during use, waste heatreleased from the combustion engine powers at least one internalgenerator of the multiple-effect absorption chiller, whichmultiple-effect absorption chiller produces chilled water, and thesystem being sized and configured to circulate at least a portion of thechilled water through the conduit to the engine inlet chiller to coolair entering the combustion engine.